Выполни действия A 3/4-2/5= 1/3+5/12= 5/8-3/16= 1/10+7/10= 9/17+8/17= 2/5-1/3= 1/6+5/12= 5/9-4/27= 1/8+3/8= 7/10-1/2=

3/4 - 2/5 = (3 * 5 - 2 * 4)/20 = (15 - 8)/20 = 7/20;1/3 + 5/12 = (1 * 4 + 5 * 1)/12 = (4 + 5)/12 = 9/12 = 3/4;5/8 - 3/16 = (5 * 2 - 3 * 1)/16 = (10 - 3)/16 = 7/16;1/10 + 7/10 = 8/10 = 4/5;9/17 + 8/17 = 17/17 = 1;2/5 - 1/3 = (2 * 3 - 1 * 5)/15 = (6 - 5)/15 = 1/15;1/6 + 5/12 = (1 * 2 + 5 * 1)/12 = (2 + 5)/12 = 7/12;5/9 - 4/27 = (5 * 3 - 4 * 1)/27 = (15 - 4)/27 = 11/27;1/8 + 3/8 = 4/8 = 1/2;7/10 - 1/2 = (7 * 1 - 1 * 5)/10 = (7 - 5)/10 = 2/10 = 1/5;7/12 + 1/2 = (7 * 1 + 1 * 6)/12 = (7 + 6)/12 = 13/12 = 1 1/12;2/7 + 5/14 = (2 * 2 + 5 * 1)/14 = (4 + 5)/14 = 9/14;11/15 - 2/5 = (11 * 1 - 2 * 3)/15 = (11 - 6)/15 = 5/15 = 1/3;5/6 - 1/6 = 4/6 = 2/3;1/6 + 3/5 = (1 * 5 + 3 * 6)/30 = (5 + 18)/30 = 23/30.